1. Field of the Invention
The present invention relates to a vehicle speed control device of a vehicle.
2. Description of Related Art
As a device for controlling the vehicle speed of a vehicle, the device described in Japanese Patent Application Publication No. 60-215432 (JP 60-215432 A) is known. This device controls the vehicle speed in such a way that, when there is no preceding vehicle, the host vehicle travels with vehicle speed set to a preset speed and that, when there is a preceding vehicle, the host vehicle follows the preceding vehicle with a predetermined inter-vehicle distance.
The device described above has the following problem. When a preceding vehicle disappears from the road ahead while the host vehicle is controlling the vehicle speed by following the preceding vehicle that is traveling at a speed lower than the preset vehicle speed, there is a possibility that the driver of the host vehicle driver has a feeling of strangeness because the host vehicle performs an unnecessary acceleration control. For example, assume that the host vehicle is performing vehicle speed control by following a preceding vehicle on a limited-access road. In this case, if only the host vehicle enters an exit lane to exit from the limited-access road, the host vehicle may be accelerated to the preset speed because the preceding vehicle has disappeared from the road ahead. In the exit lane to an open road where the legal speed limit is low, the driver has a feeling of strangeness about an unnecessary acceleration.
Therefore, in this technical field, the development of a vehicle speed control device is desired that avoids a host vehicle's unnecessary acceleration in order to reduce the possibility that a driver has a feeling of strangeness.